By reason of the large number of automobiles operated in congested areas such as large cities, pollution of the atmosphere by the automobile exhaust gases has become an increasingly serious problem. Many efforts have been made to decrease such pollution. Among such efforts is the installation of a catalytic converter in the exhaust line of the vehicle. However, a catalytic converter is an expensive piece of equipment which materially increases the cost of a car on which it is installed. Moreover, it is not wholly effective or reliable. A further disadvantage is that it requires the use of unleaded gasoline and thereby reduces the performance of the car.
Another means that has been tried for reducing pollution is to recycle a portion of the exhaust gases by introducing it into the intake manifold of the engine. While this results in subjecting the recycled portion of the exhaust gases to a second combustion, it has the disadvantage of reducing the amount of oxygen available in the charge for combustion so that the combustion is less complete than it would be if an excess of oxygen were available.
Another approach to the problem of reducing pollution of the atmosphere by automobile exhaust gases is to provide sophisticated electronic gear for sensing relevant variables such as engine speed, engine temperature, ambient temperature and ambient pressure and controlling the fuel charge and in some instances the recycling of a portion of the exhaust in accordance with a computerized evaluation of such variables. However, such equipment is expensive and although it is theoretically effective it is so complex that malfunctioning can readily occur.
Thus although the problem of reducing pollution of the atmosphere by automobile exhaust gases has long existed and although many proposals have been made, no simple, effective and economically feasible solution to the problem has been found.